Furnace



INVENTORS RODNEY E. CHRISTIAN BY ALFRED W.WIDER STEDT 2 Sheets-Sheet 1'FURNACE R. E. CHRISTIAN ET AL o O O O 0 o o o o o a ATTO RNEYS July 6,1948.

Filed June 18, 1945 July 6, 1948. R. E. CHRISTIAN ET AL FURNACE 2Sheets-Sheet 2 Filed June 18, 1945 INVENTORS RODNEY E.CHRIST|AN 'BYALFRED W.W!DERSTEDT ATTORNEYS Patented July 6 1948 FURNACE.

Rodney E. Christian, Royal Oakpand Alfred W. Widerstedt, Detroit, Mich,assignors to Kerr Manufacturing Co., a corporation of MichiganApplication June 18, 1945, Serial No. 600,110

is, first, to eliminate moisture from themolds; second, to remove thepatterns by melting and draining on" the wax; third, to bring the" moldup to proper temperature for casting; and, fourth, to volatilize anycarbonaceous material formed by wax being absorbed into the mold.

It is the object of the invention to obtain a construction of heattreating apparatus capable of simultaneously operating upon a largenumber of molds for the purpose above described.

It is a further object to obtain a construction in which the molds canbe introduced into and removed from the heat treating apparatus with aminimum loss of heat. With these objects in view the invention consistsin the construction as hereinafter set forth.

In the drawings:

Fig. 1 is a vertical longitudinal section through the heat treatingapparatus;

Fig. 2 is a cross section therethrough;

Fig. 3 is a sectional elevation showing a plurality of molds assupported within the heating chamber and separated by spacers;

Fig. 4 is a cross section on line 4-4, Fig. 3;

Fig. 5 is a section taken on line 5-5, Fig. 2;

Fig. '6 is a modification of a plurality of plugs mounted on a singleplate;

As illustrated in Figs. 1 and 2, A is a hollow wall casing preferablyformed of sheet metal and provided with insulating material B within itshollow walls. The space within this casing is divided by a horizontalpartition into a lower air heating chamber D and an upper heat treatmentchamber E. The opposite side walls of the latter chamber are providedwith series of aligned apertures F, each of sufiicient area for thepassage of the largest mold to be treated. Extend Claim. (01. s4 193) tomeans for heat treat- I ing across the chamber between aligned aperturesF and outward therethrough are mold supporting members G. These arepreferably metal bars of V-shaped cross section adapted to retaincylindrical molds placed thereon and also to receive and convey outwardfrom the chamber any melted wax. Each bar G is removable but is normallylocked in position by a hook member G on the underside of the barengageable with a detent G2 on the one wall of the casing. A lug (3%also on the bottom of the bar extends adjacent to the inner face of theopposite wall of the casing thereby holding the bar from accidentallongitudinal displacement. Within the chamber D is arranged an airheater preferablyan electrical heater H. Also within this chamber is afan I having its shaft extending outward through the Wall of the casingand actuated from a motor J and belt transmission J. The fan is soarranged that air will be withdrawn from the chamber D and propelledupward into-the chamber E through a passage at one end of the horizontalpartition C. A similar passage at the opposite end of said horizontalpartition permits the air or a portion thereof to return to the chamberD thereby efiecting a constant air circulating system. Perforatedvertical partitions K and K separate the air inlet and outlet passagesfrom the work chamber E. As has been stated, the apertures F are ofsufficient area to receive the largest of the molds to be treated.However, where smaller molds are used, these apertures are reduced inarea by exchangeable filler plugs L. These are preferably formed ofsheet metal to loosely fit the apertures F and with an opening Ltherethrough corresponding to the particular mold which is to betreated. Also, the space surrounding this opening is preferably filledwith insulated material. If desired, instead of separate plugs L foreach of the apertures F, a plurality of plugs L may be mounted on asingle plate L so that they may be simultaneously engaged with orremoved from the whole series of apertures F. The chamber E is alsoprovided at its top with a vent conduit M for the escape of gases andvapor from said chamber.

In operation, the apertures F having been reduced in area by theexchangeable plugs L to correspond to the particular molds beingtreated, the operator successively introduces molds, such as N, into thechamber E. This is accomplished by first placing a mold on the portionof the trough G which extends outward through the wall of the casing andthen pressing it inward by any suitable pusher. A second mold is thensimilarly placed in the trough and pressed against the first mold andthis is continued until the series extends across the chamber E.However, to provide for the escape of vapor and wax, per- .foratedspacers O are placed between successive molds. these also resting on thetrough G. After filling one trough G with molds, the same operation isrepeated in connection with another trough and so on until the wholechamber E is filled with molds, The time required for filling the entirechamber is generall sufficient to complete the heat treatment of themolds first introduced. These are then removed from the heating chamherby successively introducing untreated molds at the entrance end therebyexpelling the treated molds from the opposite end. Thus, the apparatusis used continuously without interruption for the removal of the work.

To provide for draining away the molten wax, the troughs G may beslightly inclined from one wall to the other as indicated in Fig; 3 orthe whole furnace may be slightly tilted to produce the same effect. Thetroughs G may at any time be easily removed for cleaning and thenreplaced; 1

Access to the chambers D and E is provided bya:

removable closure P in the rear wall of the casing;

One very important advantage of the 'c oristruc= tion is that theopenings in-the e'v'en throughwhich the molds are entered and expelledare 'of minimum size thereby reducing heat losses t the t j minimum. I p

What we claim as our invention is: In a heat treatment apparatus, acasing having aligned apertures in opposite sidewalls thereof,ai-trough-shaped member extending'through the low'e'rportions or saidaligned apertures and the chamber therebetween within said casing, saidmember constitutinga slideway on which molds may-be successively placedin alignment with ach other, i

advanced through and in aircommunication with said chamber and expelledthrough the aligned aperture in the opposite side wall, means forcirculating heated air within said chamber, and perforated spacersadapted to be placed between successive molds for the escape of vaporand liquid therefrom during heat treatment.

1 RODNEY E. CHRISTIAN. ALFRED W. WIDERSTEDT.

I REFERENCES CITED The following references are of record in the file ofthis patent: Q- UNITEDSTATES PATENTS 2,412,407' '--Kilbury Dec; 10',1946

